The crucial link between micro- and macro-levels is social networks used by immigrants in the migration process. A key factor here is the world capitalist economy that influenced the conditions of the sending and the receiving countries; affected the formation of the U.S. immigration policy, which prompted the Chinese immigrants to use social networks to fight hard against the discriminatory immigration policy and changed the pattern of Chinese immigration. In a word, the penetration of the world capitalist economy into peripheral countries creates a migratory population that tend to flow into developed countries. And the expansion of the world economy influences the social and economic structure of the sending and the receiving countries that also induce migration across national borders.